Air conditioning system



2 Sheets-Sheet l Filed March 4, 1938 March 28, 193 s.' M. ANDERSON ET AL AIR CONDITIONING SYSTEM .w W; W 1 NW RN n (.ZQZEI zo2 v H a m M 235:5 mm QM 0N Iflllwlfil Tm T. a m I uoaaow M n m v5.5; u E I I 0 0 M w u HWW H MW s a .7 N\ a. 2 s m mumnow QFSWG 5m F S. M. ANDERSON ET AL March 28, 1939.

' AIR CONDITIONING SYSTEM 2 Sheets-Sheet 2" Filed March 4, 1938 m z u g a vEm vh 6A Q T uU W a I a u E .M W

Patented Mar. 28, 1939 UNITED STATES PATENT OFFICE AIR CONDITIONING SYSTEM Application March 4, 1938, Serial No. 193,942

8 Claims.

for example, may, as far as the source of refrig- 'eration is concerned, be divided into two classes. In one'class, the cooling effect is obtained through the meltage of stored ice. In the other class, the cooling effect is produced by the evaporation of a volatile refrigerant. In ice systems, an excess of ice must be carried for a large portion of the ice melts through heat losses. In systems using a volatile refrigerant, the equipment must be over-sized so as to be able to take care of the maximum load.

It has been found feasible to cool railway pas-- sengercars by evaporative cooling during substantially half the time the cars are in service during the cooling season. This means that the refrigeration load should be reduced one half. The refrigeration plant could easily be reduced to one-half its normal capacity for average loads but could not take care of a maximum or peak load. For this reason, it has been proposed to continue equipping railway passenger cars with over-sized refrigeration equipment even when it is expected that evaporative cooling will be used half the time.

According to this invention, the usual refrigeration plant is reduced in size to take care of the average load during refrigerative. cooling cycles, and an auxiliary refrigeration source is cut into service to take care of above the average loads a when such are encountered.

An object of the invention is to condition air at low cost.

Another object of the invention is to provide a refrigeration plant for an air conditioning system, of a size to take care of a predetermined load, and to provide an auxiliary source of refrigeration for taking care of loads in excess of the said predetermined load.

Other objects of the invention will be apparent from the following description taken together with the drawings.

The invention will now be described with reference to the drawings, of which:

Fig. 1 is a diagrammatic view of one embodiment of a complete air conditioning system ac cording to this invention;

Fig. 2 is. a diagrammatic view of an auxiliary source of refrigeration which may be substituted for that shown by Fig. 1, and

Fig. 3 is a diagrammatic view of another em The blowers 5 draw in. outdoor air from between the dampers 6, and recirculated air from the passenger space, between the shutters I, and force the air through the washer 8 and thence into the passenger space or through the duct 9.

When the wet bulb temperature of the outdoor air'is. low enough for evaporative cooling to be effective, say as low as 60 F., the thermostat II] which is connected in a series circuit with the damper motor II, the solenoid l2 and the electric source, closes this circuit causing the motor I l to close the recircuited air dampers l and to open thefresh air dampers 6, and causing the solenoid. l2 to adjust the valve M to close off the pipe from the drain pipe l6 of the washer 8, and to open the by-pass pipe II to connect the pipe I6 to the suction of the pump I8 so that the water from the washer is continuously recirculated. At the same time as previously explained, all out-door air passes through the washer and the system operates in an evaporative cooling cycle.

The cold water source supplies cold water to the sump l9 and during the refrigerative cooling cycle as will be explained later, the pump l8 supplies cold water from the sump Hi to the washer 8. The cold Water source 20 which may include mechanical refrigeration or stored ice or any other suitable source, is sized to take care of loads below the occasional maximum expected load.

The sump 19 contains the evaporator coils 21 which are connected through the expansion valve 23 with the compartment 22 containing a compressed volatile refrigerant such for example, as anhydrous ammonia. The thermostat in the sump I9 is exposed to the water therein and acts when the source 20 is functioning at full capacity and the water in the sump is still too warm, to close a circuit including the solenoid 24, the electric source 13 and the thermostat 25 causing the solenoid 24 to partially open the valve 23 to admit ammonia for evaporation in the coils 2|. This provides for cooling the washer water until the excessive heat condition passes at which time the source 20 is able to handle the reduced load, and the auxiliary source 22 is cut out of service. The refrigerant leaving the coils 2| is No energy is consumed except as needed.

Fig. 2 illustrates an alternative auxiliary source of refrigerant. The source 22 has one or more cylinders of compressed carbon dioxide which is admitted into the coils 2| when needed. The carbon dioxide leaving the coils 2! may be discharged through the pipe 21 to the tracks.

When the wet bulb temperature of the outdoor air rises above F., the thermostat I0 causes the motor I I to partially close the dampers 6 and to partially open the dampers i. It also at this time causes the solenoid IE to adjust the valve M to close off the by-pass'pipe ll and to open the pipe l5, thus causing the drain water from the washer 8 to pass through the pipe [6 into the pipe l5 and thence into the source 20 where it is chilled. The pump l8 draws the chilled water from the sump l9 and supplies it to the washer 8. Under normal or average loads, the source 20 will be sufficient. For heavier loads, the thermo stat automatically provides additional cooling as required, from the auxiliary source 22.

The thermostat 28 in the passenger space controls conditions there by starting and stopping the pump motor 29 thus controlling the supply of cooling medium to the air Washer 8.

Fig. 3 illustrates another embodiment in which the auxiliary refrigeration source is a compressorcondenser combination, and its operation is controlled by a thermostat in the air leaving the air cooler. The compressor 32 and condenser 33 with driving motor a l take the place of the stored refrigeration source 20 of Figs. 1 and 2. The thermostat 35 starts the compressor motor 34 when the temperature of the air leaving the washer 8 indicates that the refrigerating capacity of the main source 20 is inadequate. The thermostat 35 thus performs in the system of Fig. 3, the function of the thermostat 25 in Fig. 1. It would be necessary of course to have the thermostat 55 coordinated with the thermostat 28. In the embodiment illustrated, the thermostat 28 controls the operation of the thermostat 35 through the relay 3!; which disconnects the thermostat 35 except when the washer 8 is operating to cool the air. The thermostat 35 may also be set at a higher temperature and may have a delayed action.

The thermostat 25 of Fig. 1 could of course, be exposed to the temperature of the water returned from the washer 8 and would function when the washer water became too warm to apply the reserve refrigeration.

Ifhe invention is not limited to an evaporative cooling system or even to an air washer system since its features apply to so-called dry surface cooling systems as well.

While one or more embodiments of the invention have been described for the purpose of illustration, it should be understood that the invention is not limited to the exact apparatus and arrangement described as many departures may suggest themselves to those skilled in the art without departing from the spirit of the invention.

What is claimed is:

1. An air conditioning system comprising an air cooler, refrigerating means for supplying chilled liquid to said cooler, auxiliary refrigerating means for additionally chilling said liquid, and means responsive to the temperature of the liquid from said first mentioned refrigerating means for adjusting the effectiveness of said auxiliary refrigerating means.

2. An air conditioning system comprising an air I cooler, refrigeratingmeans for supplying chilled liquid to said cooler, auxiliary refrigerating means for additionally chilling said liquid, and means" responsive to the temperature of the liquid from j said first mentioned refrigerating means for'r'enderlng said auxiliary refrigerating means effective or ineffective.

3. An air conditioning system comprising an air cooler, means forming a water sump, main refrigerating means for chilling the water in said sump, coils in the water in said sump, auxiliary refrigerating means for supplying a refrigerant for said coils, and means responsive to the temperature of the water in said sump for controlling the supply of refrigerant from said auxiliary refrigerating means to said coils.

4. An air conditioning system comprising an air cooler, means forming a water sump, main refrigerating meansfor chilling the water in said sump, evaporator coils in the water in said sump, auxiliary refrigerating means for supplying a refrigerant for evaporation in said coils, and means responsive to the temperature of the water in said sump for controlling the supply of refrigerant from said auxiliary refrigerating means to said coils.

5. An air conditioning system comprising an air cooler, refrigerating means for supplying chilled water to said cooler, a source of stored compressed volatile refrigerant, means for additionally chilling the water from said refrigerating means with refrigerant from said source, and means responsive to the temperature of the water from said refrigerating means for adjusting the effectiveness of said last mentioned means.

6. An air conditioning system comprising an air cooler, refrigerating means for supplying chilled water to said cooler, a source of stored compressed volatile refrigerant, evaporator coils exposed to the water from said refrigerating means, means for supplying refrigerant from said source for evaporation in said coils, and means responsive to the temperature of said water from said refrigerating means for adjusting the effectiveness of said last mentioned means.

'7. An air conditioning system for supplying cold air to a room comprising an air cooler, main refrigeratingmeans for supplying chilled liquid to said cooler, a room thermostat for controlling the effectiveness of said means, auxiliary refrigerating means for additionally chilling said liquid, and an' air stream thermostat, in the path of the air leaving said cooler for rendering said auxiliary refrigerating means effective when said main refrigerating means under control of said room thermostat. is ineffective to maintain a predetermined minimum temperature of the air leaving said cooler.- y

8. An air conditioning system for supplying cold air to a room comprising an air cooler, main refrigerating means for supplying chilled liquid to said cooler, a roomthermostat for contmlling the eifectiveness of said means, auxiliary refrigerating means for additionally chilling szrd liquid, an air stream thermostat in the path of the air leaving saidzcooler for. rendering said auxiliary refrigerating means effective when said main refrigerating-ameans under control of said room thermostat is ineffective to maintain a predetermined minimum temperature of the air leaving said cooler,:;-and:.means controlled by said room thermostat,for rendering said air stream z rthermostat inoperative when the air in said room is at the desired: temperature.

- SAMUEL MfANbERsoN.

. -ROBERT VT. PALMER. 

